Do we need to do anything about this tag?

No. I honestly see no risk of confusion, which is the only reason that would warrant addressing an ambiguity.

The distinction you portray is unclear, fictitious, or accidental. For instance, the notion of moving target is inconsistent with characterizing a snapshot question as "What was the law on X in year Y?". That is because the historical fact that "in year Y the law on X said abc" will never change: There is no moving target.

In the example you cite as of first category, the answer is of the form "In year YYYY" (or some specific point in time). Your classification entails the oddity that the question is of the first category, and yet the answer inevitably will have the form of snapshot(s) (and hence, fit the second category instead).

There are cases where the selection of tag would be driven by inconsequential wording rather than by the substance of the question. The example about Sweden and Nintendo 64, which you classify as of second category, would have to be classified as first category if only the OP asked "When (if ever) did Sweden outlaw xyz?".

None of these scenarios touches on the substance of legal principles, which is the reason of being of tags on LawSE.

Should the tag be limited to questions about law in a historical context, with snapshot questions ("What was the law on X in year Y?") retagged to something like old-law or obsolete?

No. Also your characterization of snapshot questions entail a historical context, and hence they overlap what you group as first category.

Furthermore, retagging is too burdensome, prone to errors or subjectivity, volatile, and unnecessary. For instance, someone on LawSE would have to repeatedly put the "obsolete" tag back and forth on any posts about court decisions that get reversed/overruled by each upper court.

Just like the wording of a question can be applied to forcibly fit either category, others' subjective interpretation of a question could lead to repeatedly switching categories.

It is common knowledge that laws and legal precedents undergo changes. People who need to know the current state of affairs can get from certain answers a starting point, but they ultimate need to corroborate that the sources provided in those answers remain in force. Contributors on LawSE have no obligation to ensure that their answers are forever kept up-to-date.

Do we need to do anything about this tag?

No. I honestly see no risk of confusion, which is the only reason that would warrant addressing an ambiguity.

The distinction you portray is unclear, fictitious, or accidental. For instance, the notion of moving target is inconsistent with characterizing a snapshot question as "What was the law on X in year Y?". That is because the historical fact that "in year Y the law on X said abc" will never change: There is no moving target.

In the example you cite as of first category, the answer is of the form "In year YYYY" (or some specific point in time). Your classification entails the oddity that the question is of the first category, and yet the answer inevitably will have the form of snapshot(s) (and hence, fit the second category instead).

There are cases where the selection of tag would be driven by inconsequential wording rather than by the substance of the question. The example about Sweden and Nintendo 64, which you classify as of second category, would have to be classified as first category if only the OP asked "When (if ever) did Sweden outlaw xyz?".

None of these scenarios touches on the nature of questions or branches of law, which are the reason of being of tags on LawSE.

Should the tag be limited to questions about law in a historical context, with snapshot questions ("What was the law on X in year Y?") retagged to something like old-law or obsolete?

No. Also your characterization of snapshot questions entail a historical context, and hence they overlap what you group as first category.

Furthermore, retagging is too burdensome, prone to errors or subjectivity, volatile, and unnecessary. For instance, someone on LawSE would have to repeatedly put the "obsolete" tag back and forth on any posts about court decisions that get reversed/overruled by each upper court.

Just like the wording of a question can be applied to forcibly fit either category, others' subjective interpretation of a question could lead to repeatedly switching categories.

It is common knowledge that laws and legal precedents undergo changes. People who need to know the current state of affairs can get from certain answers a starting point, but they ultimate need to corroborate that the sources provided in those answers remain in force. Contributors on LawSE have no obligation to ensure that their answers are forever kept up-to-date.